Operating System Transfer

When I first purchased my computer it had only a 80 gb hard drive. Since then I have installed a 300 gb secondary hard drive for more space. My question is, my space is running out on my 80gb "C" drive. Can I transfer my Operating System files to the secondary drive and then use it as my boot drive, and what would I need to do to accomplish this. Thank you so much for any help. I am running Vista Home Premium SP1.